We have discussed this topic on the DR several times, and for me the issue with professional football is about price. My brother and I are both Cowboys fans. Back in the 90's we used to be able to buy tickets to see them play at Giants stadium every year by searching ebay or even buying scalped tickets the day of the game for a reasonable price. The whole day would be less than $100 each, and it helped to keep us connected to the NFL.
Now I have a family of four and it would cost me well over $1000 to go to a game. That includes parking and concessions. I would have loved to take my kids to a few games but it is just so damn expensive. Both my daughters play soccer, so we go see the Red Bulls play a couple times a year, and the women's national soccer team whenever they are local (NJ). Either one of those options are far less expensive and far more family friendly.